From: "Zhou Qiao(周侨)" <qiaozhou@asrmicro.com> To: "catalin.marinas@arm.com" <catalin.marinas@arm.com>, "will.deacon@arm.com" <will.deacon@arm.com>, "mark.rutland@arm.com" <mark.rutland@arm.com>, "suzuki.poulose@arm.com" <suzuki.poulose@arm.com>, "mingo@kernel.org" <mingo@kernel.org>, "marc.zyngier@arm.com" <marc.zyngier@arm.com>, "andre.przywara@arm.com" <andre.przywara@arm.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org> Subject: RE: [PATCH V2] arm64: traps: disable irq in die() Date: Fri, 21 Jul 2017 07:38:42 +0000 [thread overview] Message-ID: <fae0379a29ec447e9dcc743d7aee194f@mail2012.asrmicro.com> (raw) In-Reply-To: <1499419774-14563-1-git-send-email-qiaozhou@asrmicro.com> Hi Maintainers, Could you please help to take a look and give some comments? Thanks in advance. Best Regards Qiao -----Original Message----- From: Zhou Qiao Sent: Friday, July 07, 2017 5:30 PM To: catalin.marinas@arm.com; will.deacon@arm.com; mark.rutland@arm.com; suzuki.poulose@arm.com; mingo@kernel.org; marc.zyngier@arm.com; andre.przywara@arm.com; linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org Cc: Zhou Qiao Subject: [PATCH V2] arm64: traps: disable irq in die() In current die(), the irq is disabled for __die() handle, not including the possible panic() handling. Since the log in __die() can take several hundreds ms, new irq might come and interrupt current die(). If the process calling die() holds some critical resource, and some other process scheduled later also needs it, then it would deadlock. The first panic will not be executed. So here disable irq for the whole flow of die(). Signed-off-by: Qiao Zhou <qiaozhou@asrmicro.com> --- arch/arm64/kernel/traps.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 0805b44..2e2ff88 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -274,10 +274,12 @@ static DEFINE_RAW_SPINLOCK(die_lock); void die(const char *str, struct pt_regs *regs, int err) { int ret; + unsigned long flags; + + raw_spin_lock_irqsave(&die_lock, flags); oops_enter(); - raw_spin_lock_irq(&die_lock); console_verbose(); bust_spinlocks(1); ret = __die(str, err, regs); @@ -287,13 +289,15 @@ void die(const char *str, struct pt_regs *regs, int err) bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - raw_spin_unlock_irq(&die_lock); oops_exit(); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); + + raw_spin_unlock_irqrestore(&die_lock, flags); + if (ret != NOTIFY_STOP) do_exit(SIGSEGV); } -- 2.7.4
WARNING: multiple messages have this Message-ID (diff)
From: qiaozhou@asrmicro.com (Zhou Qiao(周侨)) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH V2] arm64: traps: disable irq in die() Date: Fri, 21 Jul 2017 07:38:42 +0000 [thread overview] Message-ID: <fae0379a29ec447e9dcc743d7aee194f@mail2012.asrmicro.com> (raw) In-Reply-To: <1499419774-14563-1-git-send-email-qiaozhou@asrmicro.com> Hi Maintainers, Could you please help to take a look and give some comments? Thanks in advance. Best Regards Qiao -----Original Message----- From: Zhou Qiao Sent: Friday, July 07, 2017 5:30 PM To: catalin.marinas at arm.com; will.deacon at arm.com; mark.rutland at arm.com; suzuki.poulose at arm.com; mingo at kernel.org; marc.zyngier at arm.com; andre.przywara at arm.com; linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org Cc: Zhou Qiao Subject: [PATCH V2] arm64: traps: disable irq in die() In current die(), the irq is disabled for __die() handle, not including the possible panic() handling. Since the log in __die() can take several hundreds ms, new irq might come and interrupt current die(). If the process calling die() holds some critical resource, and some other process scheduled later also needs it, then it would deadlock. The first panic will not be executed. So here disable irq for the whole flow of die(). Signed-off-by: Qiao Zhou <qiaozhou@asrmicro.com> --- arch/arm64/kernel/traps.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 0805b44..2e2ff88 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -274,10 +274,12 @@ static DEFINE_RAW_SPINLOCK(die_lock); void die(const char *str, struct pt_regs *regs, int err) { int ret; + unsigned long flags; + + raw_spin_lock_irqsave(&die_lock, flags); oops_enter(); - raw_spin_lock_irq(&die_lock); console_verbose(); bust_spinlocks(1); ret = __die(str, err, regs); @@ -287,13 +289,15 @@ void die(const char *str, struct pt_regs *regs, int err) bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - raw_spin_unlock_irq(&die_lock); oops_exit(); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); + + raw_spin_unlock_irqrestore(&die_lock, flags); + if (ret != NOTIFY_STOP) do_exit(SIGSEGV); } -- 2.7.4
next prev parent reply other threads:[~2017-07-21 7:39 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-07-07 9:29 [PATCH V2] arm64: traps: disable irq in die() Qiao Zhou 2017-07-07 9:29 ` Qiao Zhou 2017-07-21 7:38 ` Zhou Qiao(周侨) [this message] 2017-07-21 7:38 ` Zhou Qiao(周侨) 2017-07-21 8:32 ` Will Deacon 2017-07-21 8:32 ` Will Deacon 2017-07-21 9:57 ` qiaozhou 2017-07-21 9:57 ` qiaozhou
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